Machining after extrusion affords greater versatility of operation since it is thus possible to extrude cylindrical structures at high speed and to store them for the purpose of subsequent machining of the various types of cables or cable elements corresponding to the programme of production. The outside dimensions of the cables will be standardized, as well as the nature of the outer sheathing whereby the diameter of the optical fibre support will be fixed. However the number of optical fibres and the geometry of the grooves will vary from one type of cable to the other. The driving speed which can be used in machining the structure according to the present invention is higher than that which can be used for direct extrusion of the profiled structure. There is therefore an economical advantage in producing cables or cable elements according to the present method.
Machining of support for optical fibre cables according to the present invention favours the constitution of a continuous production line for the cables by coupling means for the manufacture of the grooved support according to the invention with fibre-positioning means, because the machining method according to the invention renders possible stopping of the line and restarting of the production line without creation of any discontinuity in the rod. When the grooved rod is obtained directly by extrusion stopping and restarting of the production line create irregularities on the support that make the cable lengths unusable and increase the overall cost of the cable length unit.